Moonshot AI announced Kimi K3 on July 16, 2026 — a 2.8-trillion-parameter Mixture-of-Experts model that the company says is now the largest open-weight model in the world. Early reporting pegs it as routing to 16 of 896 experts per token (around 50B active), though Moonshot hasn't officially confirmed the exact active-parameter count.
Two new pieces of architecture
K3 leans on two internally-developed components: Kimi Delta Attention (KDA), a linear attention mechanism refining Gated DeltaNet with finer-grained gating over the model's recurrent memory — reportedly delivering up to 6.3x faster decoding at million-token contexts — and Attention Residuals, described as a drop-in replacement for standard residual connections that gives consistent gains as the model scales. Combined with a 1M-token context window and native visual understanding, this is Moonshot betting on efficiency-at-scale rather than just adding parameters.
An always-on reasoner
Unlike models that toggle between a fast mode and a "thinking" mode, K3 ships with reasoning on by default — Moonshot calls it "thinking mode," and it's not something you switch on for hard problems, it's just how the model runs.
Where it actually lands
On GDPval-AA v2 — a benchmark spanning real-world tasks across 44 occupations and 9 industries — K3 scored 1,687, good for third place overall, behind only Claude Fable 5 Max (1,815) and GPT-5.6 Sol Max (1,747.8), and ahead of Claude Opus 4.8 (1,600). In task-automation benchmarks it actually took first place in four of eight, including Automation Bench, SpreadsheetBench 2, and BrowseComp — areas where raw benchmark scores don't always predict who wins on messy, real work.
Pricing tells its own story: $15 per million output tokens, well above GLM-5.2's $4.40 or DeepSeek V4's $0.87, but still a fraction of what the closed frontier charges for comparable capability — roughly Opus-4.8-class performance at something closer to Sonnet-5-era pricing.
Not out yet, but close
The announcement landed just ahead of the 2026 World Artificial Intelligence Conference in Shanghai. Full model weights are scheduled to follow on July 27 — so for now, K3 is a benchmark story more than a downloadable one, but if the numbers hold once weights are public, it's a serious marker for how close open-weight models have gotten to the closed frontier.
Links
- Announcement: Kimi K3 — Moonshot AI